Hole underreamer



Dec. 17, 1940.

Va. B. DUNLAP, JR

HOLE UNDERREAMER iled Aug. 16, 1939 3 Sheets-Sheet l 7 s l a 6 0 s E W;glvwo/wbo'u M HMA/v B. Dun mg J1. I I I2 Dec. 17, 1940. VV. B. DUNLAP,JR

HOLE UNDERREAMER Filed Aug. 16, 1939 3 Sheets-Sheet 2 Ill-EFL." l

Fl/l ml Dec. 17, 1940. w. B. DUNLAP', JR

HOLE UNDERREAMER Filed Aug. 16, 1939 3 Sheets-Sheet 3IIIIIIIIIIIIVIIJI/II/A Patented Dec. 17, 1940 UNITED STATES PATENTOFFICE HOLE UNDERREAMER Weyman B. Dunlap, In, Houston, Tex. ApplicationAugust 16, 1939, Serial No. 290,405 9 Claims. (Cl. 255-66).

This invention relates to an underream'er.

An object of the invention is to provide an underreamer speciallydesigned for underreaming, or enlargin'g, the lower ends of holes, or

bores, for receiving foundation piers, piling and the like. I

It is another object of the invention to provide an underreamer shapedto be readily lowered into a hole or bore previously formed and havingoutwardly movable blades, or cutters, whereby the lower end of the boremay be gradually enlarged to the desired extent, said blades beingretractable to permit the ready withdrawal of the underreamer from'thebore, or hole. Theunderreamed 1 bore may then be filled with plastic,concretious material which, when set, will have a relatively largesupporting base.

The invention also embodies novel means for expanding, or retracting,the reaming blades, or

cutters.

Another object of the invention is to provide an underreamer having asubstantiallycylindrical retainer, or bucket, permanently closed at itslower end and having side slots through which the reaming blades work,said blades being shaped" to gradually move the cuttings inwardly, asthe underreamer is rotated, to collect the cuttings within the containeror bucket, and, upon retraction of the reaming blades to close said sideslots and retain the cuttings within the container upon withdrawal ofthe underreamer. The invention also embodies novel means for centeringthe underreamer in the bore during the rotation or operation thereof aswell as means for collecting, into the bucket, the loose earth that maybe at the bottom of the bore.

The invention also embodies novel guide means for accurately guiding thereaming blades;

With the above and other objects in view the 40 invention has particularrelation to certain novel features of construction, operation andarrangement of parts, an example of which is given in this specificationand illustrated in the accompanying drawings, wherein: 40 Figure 1 showsa side elevation of the underreamer, partly in section; showing-thereamer blades retracted.

Figure 2 shows a side elevational view, partly in section, taken atright angles to the view shown 50 in Figure l. I

Figure 3 shows a vertical, sectional view showing the reaming blades inexpanded, or active, position.

Figure 4 shows a top plan view, showing the as reaming blades in activeposition.

Figure 5 shows a cross-sectional view taken on the line 5-5 of Figure 1.

Figure 6 shows a lower end view, and

Figure 7 shows a side elevation showing the reamer inaction. 5

Referring now more particularly to the drawings wherein like numerals ofreference designate the same parts in each of the figures the nuineral idesignates a container, or bucket, preferably cylindrical in shape andwhose lower end 10 is permanentlyxclosed by the lower end plate, orbottom, I, having the centralpilot 3 which is of an inverted, conicalshape. 0n opposite sides of the pilot the lower endof the bucket hasapproximately radial slots 4, 4' and behind them the 15 scrapers 5, 5,which are forwardly pitched so as to gather the loose earth on thebottom of the bore and direct it through the slots 4 into the bucket, orcontainer, I.

At the upper end of the bucket there is a 20 transverse plate 6 whichextends a selected distance down into the bucket and whose margins maybe secured to the walls of the bucket in any preferred manner as bywelding.

On opposite sides of the plate 6 there are the 25 diametrically opposedside slots 1, I, which extend :from adjacent the upper end'of the bucketdownwardly to the lower end the'reof.

On opp s te sides of the fixed plate 6. are the reinforcing plates 8, 8,whose upper ends are 0 embraced by the plate-like jaws 9, 9. The fixedplate 6 has a vertical bearing slot ill, at its upper end and a clampbolt, Ii is fitted through aligned bearings in the overlapping ends ofthe plates 8 and Jaws 9 and is fitted also through the slot I0 as moreclearly shown in Figure 2. The plates 8 have the downwardly andoutwardly curved arcuate slots i2, I! cut therethrough to receive theguides studs l3, II which are anchored to the fixed plate 8. These slotsare covered by the 40 plate-like blades I4, I! which are fastened, inany preferred manner, as by welding. to the forward sides of thecorresponding reinforcin plates 8, I. The outer margins of the blades IIare forwardly curved, as more accurately shown in Figures 4. and 5 andterminate in the scraping or reaming edges II, II. The curvature of saidblades at their lower ends is such that when the blades are in retractedposition they will substantially close the slots 1 as indicated inFigure 5 5 so as to retain the cuttings in the container, or bucket, I.

The upper ends of the plate-like jaws 9, 9 are secured, preferably bywelding, to the lower end of the upstanding driving socket member i6which is preferably square in horizontal, crosssection. It is providedto receive the correspondingly shaped lower end of a driving stem I!which may be retained therein by means of the crosspin l8 fitted throughthe socket member and the driving stem as shown in Figures 1 and 7.

In operation the blades will be in retracted position within the bucketI as shown in Figures 1 and 2 when lowered into the hole l9. When theunderreamer lands on the bottom of the hole the pilot 3 will penetrateinto the formation and will hold the bucket centered during rotation.The driving stem I! may then be rotated in an appropriate direction andby any suitable mech anism provided for the purpose. The downward thrustof the driving stein will tend to move the plates 8 and blades i4downwardly, the clamp bolt H moving downwardly in the slot Ill. Duringthis downward movement of the plates, the blades will also be graduallyexpanded, that is, their lower ends will be moved radially outwardly dueto the pins, or studs, l3 engaging in the outwardly curved cam shapedgrooves I2; It, said blades moving outwardly through the slots 7 andfinally reaching their extreme outer position as shown in Figures 3 and7.

As the blades move outwardly they will also gradually move downwardly sothat their lower ends move, or thrust, outwardly in a horizontaldirection to the end that the lower end of the bore, when underreamed,will lie in a horizontal plane as shown in Figure 7. To accomplish thisthe lower ends of the blades l4 are cut onthe diagonal, as shown inFigures 1 and 2, and terminate in sharp cutting edges. As theunderreamer is rotated the blades will come into cutting contact withthe sides of the hole and the formation will be gradually reamed awayfrom the side walls at the bottom as the blades are progressivelyexpanded. The forward curvature of the blades will gradually force thecuttings inwardly through the side slots I and when the upper ends ofthe slotsl2 engage the pins or studs I3 the blades will be fullyexpanded and the underreaming of the bore will be fully accomplished.The range of outward movement of the blades-and the consequentenlargement of the bore may be determined by the length of the slots l0,l2 and the size of the blades.

Thereu'pon the underreamer may be lifted out of the boreby an upwardpull on the driving stem ll. This will operate first to retract theblades inwardly and when the clamp bolt H reaches the upper end of theslot III, the entire tool will then be moved upwardly and may becompletely withdrawn from the bore. When the tool reaches the groundsurface the driving stem may again be lowered thus moving the bladesoutwardly and rendering the interior of the bucket accessible so thatthe contents thereof may be discharged.

The drawings and description are illustrative merely, while the broadprinciple of the invention will be defined by the appended claims.'

What I claim is:

1. An under reamer comprising a cylindrical bucket having side slots, atransverse supporting plate anchored in the top of the bucket and havinga vertical slot, lateral studson the plate, plate-like reamers alignedwith said side slots and having cam grooves which receive said studs,driving means, a bolt working through said vertical slot and forming apivoted connection between the driving means and reamers whereby thedownward movement of the driving means relative to said supporting platewill cause the outward movement of the lower ends of the reamers.

2. A tool for underreaming holes comprising a bucket shaped to enter thehole and having side slots, a supporting plate anchored in the bucketbetween said side slots and having a vertical slot, reamers on oppositesides of the plate in alignment with the side slots. whose outer and.lower margins terminate in cutting edges, driving means embracing theupper ends of the reamers, means forminga pivotal connection between thedriving means and reamers and passing through the slot of said plate,operative connections between the plate and. reamers comprisingcooperating studs and cam shaped bearings whereby upon downward movementof the'reamers in the bucket will cause the outward movement of thelower ends of the reamers.

3. A tool for underreaming earth holes comprising a bucket shaped toenter the hole and having side slots, a transverse plate in, andanchored to, the bucket between the side slots and having a verticallyelongated bearing, reamers arranged to work through the side slots,driving means for rotating the tool, means pivotally connecting thereamers to the driving means and working in the bearing, said plate andreamers being provided, one with studs and the other with cam grooves toreceive the studs whereby upon downward movement of the reamers in thebucket the lower ends of the reamers will be moved outwardly.

4. A tool for underreaming holes comprising a bucket shaped to enter thehole and having side slots, a transverse supporting element in, andanchored to, the bucket and having a vertically elongated bearing,reamers arranged to work through the side slots, driving means forrotating the tool, means pivotally connecting the reamers to the drivingmeans and working through said bearing, said reamers having cam shapedgrooves Whose lower ends an outwardly turned, reamer guides on saidfixed element projecting into said grooves whereby upon down-' wardmovement of the reamers in thebucket the lower ends of the reamerswillbe moved outwardly.

5 A tool for underreaming holes in the earth comprising a bucket shapedto enter the hole and having sideslots, a supporting element in, andanchored to, the bucket and having a vertically elongated bearing,plate-like reamers arranged to work through said side slots, drivingmeans for rotating the tool and including platelike jaws embracing theupper ends of the reamers and means pivotally connecting said reamers tosaid jaws and working through said bearing, said supporting element andreamers being provided one with cam grooves and the other with meansprojecting into said grooves whereby upon downward movement of thereamers relative to the bucket the lower end of the reamers will bemoved outwardly.

6. A reamer formed with a blade and a reinforcing plate behind theblade, means for slidably supporting the reamer, said plate having adownwardly and outwardly curved cam groove therein, the lower'and outermargins of the blade terminating in forwardly directed edges.

'7. A tool for underreahring holes in the earth comprising a bucketshaped to enter the hole and having a side slot, a reamer in the bucketaligned with said side slot, said reamer being formed of a blade and areinforcing plate behind and secured to the blade, means for slidablysupporting the reamer, a downwardly and outwardly curved cam on thereamer and means fixed relative to the bucket and .arranged to cooperatewith the cam to move the lower end of the blade outwardly upon downwardmovement 01' the blade relative to the bucket.

8. A tool for underreaming earth holes comprising a bucket shaped toenter the hole and having side slots, asupporting element in, andanchored to, the bucket between the side slots and having a verticallyelongated bearing, reamers arranged to work through the side slots,driving means for rotating the tool, means pivotally connecting thereamers to the driving means and working in the bearing, said supportingelement and reamers being provided, one with studs and the other withcam grooves to receive the studs whereby upon downward movement of thereamers in the bucket the lower ends of the reamers will be movedoutwardly.

9. A tool for underreaming holes in the earth comprising a bucket shapedto enter the hole and having a side slot, a reamer in the bucket alignedwith-the side slot, said reamer being formed of a blade and areinforcing plate behind and secured to the blade, means for slidablysupporting the reamer, said reamer and bucket being provided one with anoutwardly curved cam and th other with means fixed thereon and arrangedto cooperate with the cam to move the lower end of the blade outwardlyupon downward movement of the blade relative to the bucket.

- WEYMAN B. DUNLAP, JR.

